The present invention generally relates to protective garments such as the type worn by fire fighters. More particularly, the present invention is directed to a protective garment having a water resistant outer shell. In particular, an outer shell made according to the present invention has proven to be able to retain its primary water resistant properties even after undergoing 30 laundry cycles.
Protective garments worn by fire fighters are designed to perform several functions. Of these, protection from heat and flame are perhaps the most important characteristics of the garments. In addition to providing protection from heat and flame, the garments, however, should be as light as possible, should provide some breathability and should encumber the wearer as little as possible.
Conventional fire fighter garments are generally constructed having a number of discrete layers. Typically, these layers include an outer shell, a moisture barrier layer, a thermal barrier layer, and an inner lining. The layers are generally made from appropriate thermally-resistant materials to provide protection against heat and flame.
In the past, one difficulty that has been encountered in designing protective garments to be worn by fire fighters is to prevent the garments from absorbing and retaining moisture. For instance, protective garments worn by fire fighters usually become wet during use due to external exposure to extinguishing water or rain. Also, fire fighter garments can become wet due to the absorption of perspiration given off by the wearer. Unfortunately, when the protective garment absorbs moisture, the characteristics and properties of the garment can be adversely affected. For example, when retaining moisture, the protective garment can become significantly heavier.
Besides increasing in weight, the presence of moisture within a protective garment also adversely affects the thermal properties of the garment making the garment less effective in shielding its wearer from thermal heat. In particular, since water is a much better heat conductor than air, the rate of heat transfer through the garment increases. Also, it has been discovered that as water heats up in a protective garment, the water can turn to steam under exposure to heat and actually burn a person wearing the garment.
Ultimately, when protective garments as described above become wet or soaked with water or other fluids, the garments become hot and uncomfortable to work in due to the increased weight and due to the increased rate of heat transfer through the garment. As a consequence, a wearer can only spend a limited amount of time working or performing tasks in the garment due to the possibility of heat stress.
In the past, in order to prevent water from being absorbed by protective garments worn by firemen, the garments have been treated with a water resistant composition. The water resistant treatments applied to conventionally made protective garments, however, have not proven to be durable and have been found to become ineffective after the garment has been placed in use for a period of time. In particular, it has been discovered that conventionally applied water resistant treatments become significantly degraded when the protective garment is washed. Specifically, it has been found that the water resistant treatments begin to degrade only after five (5) laundry cycles and typically lose most of their effectiveness after ten (10) laundry cycles.
As such, a need currently exists for an improved water resistant fabric and protective garment to be worn by fire fighters. More particularly, a need exists for a method of applying a water resistant treatment to a protective garment that will not degrade over a period of time and that can withstand normal laundering.
The present invention recognizes and addresses the foregoing disadvantages, and others of prior art constructions and methods.
Accordingly, an object of the present invention is to provide an improved protective garment suitable for use by a fire fighter.
It is another object of the present invention is to provide a protective fabric for making garments that has been treated with a durable water resistant treatment.
Still another object of the present invention is to provide a protective fabric having a water resistant treatment that can withstand normal laundering.
It is another object of the present invention to provide a protective garment for fire fighters that contains a durable water resistant treatment applied to an exterior shell that allows the garment to maintain a spray rating of at least 70 even after 30 laundry cycles.
These and other objects of the present invention are achieved by providing a fabric for constructing a protective garment suitable for use by a fire fighter. The protective garment includes an inner lining configured to cover a predetermined portion of a wearer""s body. The inner lining is positioned so as to be placed adjacent to the wearer""s body during use. An outer shell made from the above fabric covers the inner lining and is made from a fire resistant material.
In accordance with the present invention, a durable water resistant treatment is incorporated into the outer shell. The durable water resistant treatment is affixed to the outer shell such that the outer shell maintains a spray rating of at least 70 even after 30 laundry cycles, and, in some applications, maintains a spray rating of at least 70 even after 50 laundry cycles. In an alternative preferred embodiment of the present invention, the outer shell is constructed so as to maintain a spray rating of at least 80 after 20 laundry cycles.
Besides maintaining a high spray rating, an outer shell constructed in accordance with the present invention also maintains very good water absorption ratings and dynamic water absorption ratings after being laundered. For instance, after five laundry cycles, the outer shell has been found to maintain a water absorption rating of less than about 8%, particularly less than about 6%, and in a preferred embodiment less than about 4%. The outer shell can have a dynamic water absorption rating of less than about 15% after ten laundry cycles, particularly less than about 12% after ten laundry cycles, and more particularly less than about 10% after ten laundry cycles. After twenty laundry cycles, the outer shell maintains a dynamic water absorption rating of less than about 18%, more particularly less about 15%, and preferably less than about 12%.
In one embodiment, the outer shell can be made from a woven fabric, such as having a plain, twill or rip stop weave. The material used to make the outer shell can be an aramid polymer or can be a mixture of an aramid polymer and polybenzimidazole. The woven fabric used to make the outer shell can have a weight of from about 5.5 ounces per square yard to about 8 ounces per square yard, and particularly at a weight of about 7.5 ounces per square yard. Further, a thermal barrier layer can be positioned between the outer shell and the inner lining.
The durable water resistant treatment applied to the outer shell can contain a fluorocarbon polymer. The water resistant treatment can be applied to the outer shell as a solution and then later cured or dried by heating the outer shell fabric.
These and other objects of the present invention are also achieved by providing a process for producing a water resistant fabric particularly well adapted for use as an exterior covering for a fire fighters protective garment. The process includes the steps of providing a fire resistant material. For instance, the fire resistant material can be a woven fabric made from a fire resistant polymer, such as an aramid polymer. In one embodiment, the fire resistant material is scoured, such as by being exposed to an alkaline solution. After scouring, the material is dried.
Once dried, a durable water resistant treatment, such as a fluorocarbon polymer solution, is then applied to at least one side of the fire resistant material. Once the water resistant treatment is applied to the material, the material is heated until the treatment is dried and cured. In particular, according to the present invention, the durable water resistant treatment is affixed to the fire resistant material such that the material maintains a spray rating of at least 70 even after 30 laundry cycles.
Other objects, features and aspects of the present invention are discussed in greater detail below.